Yesterday, a paralyzed man strapped on a pair of robotic legs and stepped out a hotel door in midtown Manhattan

Photo: Eliza Strickland Robert Woo demonstrates that exoskeletons are ready to come out of the clinic and into the streets.

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Yesterday, a paralyzed man strapped on a pair of robotic legs and stepped out a hotel door, joining the flow of rushing pedestrians on a sidewalk in midtown Manhattan.

The user, Robert Woo, was demonstrating a new exoskeleton unveiled this week, the ReWalk Personal 6.0 from Israel’s ReWalk Robotics. He got a few curious looks as he strode forward in his sleek black gear, but the fast-walking New Yorkers didn’t slow down or clear space for him.

Video: Eliza Strickland/IEEE Spectrum
A short clip of exoskeleton user Robert Woo during his stroll in New York City.

That integration into the normal pace of life is what ReWalk has been aiming for. “The design has always been based on community use,” CEO Larry Jasinski told IEEE Spectrum in an interview just before the demo. He explained that the inventor of the ReWalk system, Amit Goffer, didn’t want to build an exoskeleton that could only be used in physical therapy settings or only within the safety of the home. “He always asked, ‘What will make this functional in the community? Can it go over a curb?’ ”

U.S. regulators approved a prior version of the ReWalk system for people with spinal cord injuries, and cleared it for both clinical and personal use. It’s the only exoskeleton to receive that wide-ranging clearance thus far, meaning it’s the first exoskeleton to make it out of the hospital and into the wild. Jasinski says 66 people have purchased ReWalks so far and brought them home. Of those first purchasers, Jasinski says 11 got reimbursement from their insurance providers.

The company seems to be pushing ahead of its closest competitor, Ekso Bionics, whose exoskeleton is approved only for clinical use under medical supervision. The third and newest entry into the market, the Indego from the medical device company Parker Hannifin, is currently undergoing clinical trials to support its bid for regulatory approval in both clinical and personal use.

The basic mechanics of the ReWalk 6.0 haven’t changed from prior versions: It still uses servos in the hips and knees to provide walking power, and uses accelerometers to detect when a user like Woo has shifted his weight and is ready to take his next step. But there are several important hardware upgrades. The leg braces are slimmed down, the support straps distribute the weight more evenly around the body, and the backpack that previously housed the processor has been replaced by a smaller fannypack.

Woo, an architect with a keen design sense, tried out the previous ReWalk model on many occasions—and offered many suggestions for improvements. For example, the prior version’s straps abraded the skin around his knee, but redistributing the weight through abdominal and thigh straps fixed the problem. “ReWalk really listened to its users,” he said.

Woo also counseled the company to focus on making it easy for a user to don the ReWalk. That could make the difference between a device that someone wants to use every day, he said, and one that ends up in a closet. Woo compared his experience with an electrical stimulation rehab bike he brought home soon after his accident, which required him to plaster his legs with electrodes before starting his exercise. “It took 30 minutes just to strap into it,” he said. “By the third year, I wasn’t using it anymore.”

To address that concern, ReWalk changed its prior leg braces, which featured struts on both the inside and outside of each leg, to simpler braces with struts only on the outside. That change makes it easier to get into gear. What’s more, Woo said the increased abdominal support now allows him to bend over while sitting to put on the legs himself, without fear of toppling forward. With the previous model, a helper always attached the legs. “I can be ready to stand up [in the ReWalk 6.0] in less than 10 minutes,” Woo said.

The software upgrades for the ReWalk 6.0 provide a smoother walking gait (with less of a soldier-like marching step), an easier stopping mechanism, and a much-improved mode for ascending and descending stairs. The user wears a wristwatch-like controller to switch the suit between sit, stand, walk, and stair modes.

Jasinski stressed that the stair mode hasn’t been approved by U.S. regulators yet, so ReWalks bought here currently have that function blocked. The company has submitted the requisite paperwork to the FDA, and is hoping for that approval soon. However, that stair mode has been approved in Canada and Europe, where regulators are typically a little less stringent. And since Woo is Canadian, yesterday in the Doubletree Hotel he decided to claim the stairs for his home country, and did some demonstration climbing on the “Canadian stairs.”

Woo typically navigates New York’s cracked and cratered sidewalks in a wheelchair. He hasn’t been able to walk on his own power since 2007, when a construction crane dropped a load of steel on him, crushing his spine. He never really settled into that wheelchair though: As soon as commercial-grade exoskeletons began to appear, Woo was there as an early adopter. IEEE Spectrum met him at Mount Sinai hospital in 2011 when he first tried out an Ekso, learning to walk again after four years in his chair.

He has since become essentially a top test pilot for exoskeletons, consulting with the companies and participating in several clinical trials regarding the devices’ medical benefits. For one current study, ongoing at the VA hospital in the Bronx, Woo is walking for 100 sessions of 1 hour each. The researchers are investigating whether walking improves paralyzed people’s muscle mass, bone density, digestive function, circulation, and other systems.

Those results won’t be in for a while, but Woo said his experiences have already convinced him that exoskeletons are good for the health. While participating in a prior trial that allowed him to walk frequently, Woo says he got off the narcotic-based pain medications he hated so much, saw his digestion and circulation improve, and had fewer muscle spasms.

If such improvements are borne out, Woo said, exoskeletons won’t just be a flash in the pan. “If there were no health benefits coming from it, it would be a technology that’s purely a thrill,” Woo said.

The ReWalk 6.0 has a steep list price: US $77,000. Woo said there’s no chance his insurance provider will reimburse him: “They won’t even pay for my wheelchair,” he said. But he said he invested his money for just such a purpose, and is ready to plunk it down. He’s the first person to order the 6.0, he said proudly. “After walking in it for the first time, I said, ‘This is it, I want one for home. Sign me up!’”

Next Wednesday, Woo and his wife are going through a certification process at Mt. Sinai Hospital in NYC, which is required before they can take a unit home. Woo should get his own personal exoskeleton in a few months. And then, CEO Jasinski said, ReWalk’s team of engineers will have to get busy on the next round of design improvements. “Unless you’re really living in it, you don’t understand it,” Jasinski said. “When Robert takes it home, he’ll teach us about 100 more things.”